Take all of the money currently in circulation in any given currency, and add it all up. You'd probably imagine that the currency with the greatest value is the US dollar, although the Euro is catching up. But now the dollar has been surpassed! But not by the Euro, after all. Can you guess?

The currency with the greatest value in circulation in the world today is -- frequent flyer miles. About seven hundred billion dollars. They are often sold to credit-card companies at a valuation of two cents per mile. Perhaps not surprising to me, as I certainly have greater value in my miles than in actual cash money, but I didn't think I was typical. Hopefully United won't go out of business and leave me in the poor house. (Thanks to Wait Wait, Don't Tell Me.)